Conventionally, a wind power generation device is known in which, upon receiving wind power, blades rotate a main spindle connected thereto, and a speed increaser increases the rotation of the main spindle, thereby driving a generator. In addition, a technology is also known in which a one-way clutch is provided between the output shaft of a speed increaser and the input shaft of a generator to suppress the change in the inertia torque of the generator due to the change in wind power or the like and to reduce the load exerted to the speed increaser (for example, refer to Patent Document 1).
This one-way clutch is equipped with an inner ring provided on one side of an output shaft and an input shaft, an outer ring provided on the other side and rollers disposed in wedge-shaped spaces formed between the inner ring and the outer ring, the one-way clutch being configured such that, in the case that the rotation speed of the output shaft is higher than the rotation speed of the input shaft, the rollers are moved to narrower regions in the wedge-shaped spaces and are engaged with the inner ring and the outer ring, thereby connecting the output shaft to the input shaft so as to be rotatable integrally and being configured such that, in the case that the rotation speed of the output shaft is lower than the rotation speed of the input shaft, the rollers are moved to wider regions in the wedge-shaped spaces and are released from the engagement, thereby cutting off the connection between the output shaft and the input shaft.